Study On The Gene Differential Expression Features Under RBSDV Infected Conditions And Two New Diseases

Maize rough dwarf disease, caused by rice black-streaked dwarf virus (RBSDV), is one of major diseases in part maize main producing areas of China, Laodelphax striatellus is regarded as the main vector of this disease. At present, the occurrence area of maize rough dwarf disease is approximately150-200million hectares in our country, when this disease is serious occurrence, which can cause yield loss20-30%, even no production.The natural diseased identification was used for resistance level of458maize inbred materials, known resistance level of6maize inbrd materials were confirm by q-PCR and inoculation test, and screeing the optimal resistant-susceptible maize inbred materials for transciptome research. The results are as follow:1. The natural diseased identification of458maize inbred materials has been carried out under the high incidence pressure of maize rough dwarf disease. Base on the standard of plant height reduced rates, most of maize inbreds are susceptible types (55.9%high susceptible,36.2%for susceptibl) and only5maize inbreds (CIMBL52, CIMBL99, CIMBL69,7381and LG001) show more high resistance to maize rough dwarf disease.2. Infection identification and research technology of RBSDV are established indoor. The detection technology of single individual Laodelphax striatellus infected with RBSDV were obtained by fluorescence quantitative RT-PCR; Through making use of these technology among resistant-susceptible response stability maize inbreds which have been determined by several years repeated identification to study the relationship between the RBSDV proliferation and resistance performance of maize and proved that resistant maize inhibited the multiplication of virus is one of the important features in disease resistance.3. Resistant inbred X178and susceptible inbred Ye478were selected as the transcriptome research materials. Three group treatments were established by inoculated carriying RBSDV Laodelphax striatellus, not carrying RBSDV Laodelphax striatellus and blank control. Maize leaves samples were Collected before inoculation (0h) and after inoculation6,12,24,36,48,60h for follow-up study. Two group treatments of resistant and susceptible inbred were selected at0,24and36h for transcriptome sequencing and analysis of gene high-throughput expression profiling. The results show that:at36h after inoculation, differential expression gense were significantly more than at24h. So differential expression genes of36h time point were selected as the research focus. Further research is carried out to induced gene expression features by using Pathway significant enrichment analysis and Gene Ontology analysis methods. In susceptible maize inbred Ye478, the differentially expressed genes mainly enriched in ribosomes, non-membrane-bound organelles, chloroplasts and other important tissues and organs. These genes may be divided into three categories according to their function, namely, structural molecule activity, binding activity and catalytic activity, and involved in biological processes are mainly concentrated in the cell level biosynthesis. In the resistant inbred line X178, the differentially expressed genes with functional annotation are primarily concentrated in plastid, thylakoid, chloroplast, etc., and differentially expressed genes mainly manifested down-regulated, and involved in biological process are mainly transcribed activity and transport activity, and played a important role in synthesis and construction nucleus, chromatin organization and construction, synthesis of porphyrin metabolism and synthesis etc. biological process.4. The differentially expressed genes between the resistant maize inbred and susceptible maize inbred have been compared and classified according to expression situation and selected contrary expression situation in both different maize inbred and the differential expression genes expressed in resistant maize inbred and not expressed in the susceptible inbred. Those differential expression genes were analyzed by Pathway and Gene Ontology. The results shown that differentially expressed genes with gene annotations up-regulation in X178and down-regulation in Ye478involved in protein transport, nicotinamide metabolism, pathogen and host interactions, biosynthesis and signal transduction in photosynthetic process. The cellular component of these genes were in the cell membrane, intracellular membrane and membrane part1, the main function were transfer activity. Differentially expressed genes with gene annotations down-regulation in X178and up-regulation in Ye478involved in the starch and sucrose metabolism, pathogen and host interaction, plant hormone signal transduction. The cellular component of these genes were in external encapsulating structure, cell periphery, followed by cell membrane, intrinsic to membrane, ribonucleoprotein complex, cytoplasmic vesicle, cytoplasm. The main biological function were hydrolase activity, acting on glycosyl bonds, structural molecule activity, protein binding, protein kinase activity and adenyl ribonucleotide binding. The main biological process were lipid orientation, stress responses, biological regulation. The differential expression genes with gene annotation expressed in resistant inbred and not expressed in the susceptible inbred mainly located in cytoplasm, plasmid, plastid thylakoid chloroplast thylakoid, photosynthetic membrane, mainly involved in the photosynthetic process of biosynthesis of secondary metabolite biosynthesis, pathogen and host interactions, amino acid metabolism and other metabolic pathways, molecular function mainly were oxidoreductase activity.97related resistant genes were filtered by using Pathway significant enrichment analysis and Gene Ontology analysis methods. Those genes can be classified to five varieties.according to the biological function, namely, signal transduction, transcription factor, resistance related; Transporter activity, and some unknown genes.5. The pathogens of two new diseases, found in Xinjiang, were preliminary identified base on the morphology characteristics, molecular biological identification, pathogenitic test. Diseases which ocurred in sunflower and chickpea of Xinjiang were black stem of sunflower and Ascochyta blight of chickpea, respectively. The pathogen were Phoma macdonaldii and Ascochyta rabiei respectively.